Yep, the Faraday Effect! The sibling comment has a link to the Wikipedia page, yet for a quick video explanation and demonstration Applied Science's video on t

Yep, the Faraday Effect! The sibling comment has a link to the Wikipedia page, yet for a quick video explanation and demonstration Applied Science's video on the Faraday Effect was fantastic. It demonstrates it, explains some use cases, and also goes into how the material the light is passing through affects the strength of the magnetic induced rotation. https://www.youtube.com/watch?v=XhU-nNiAgtI https://www.youtube.com/watch?v=XhU-nNiAgtI